Many communication networks transmit data in packets. Because these methods transmit packets at random times, and because of transmission delays, synchronization of a receiver to incoming packets is needed. Thus, most transmitters send a preamble, which can be a particular sequence of identical symbols, to enable packet detection and synchronization in the receiver. Furthermore, the receiver can use the preamble to estimate several related parameters, such as a frequency offset and channel state information.
Synchronizing to the packets and estimating the related parameters become more difficult, however, when the symbols are transmitted over a plurality of frequency sub-bands according to a frequency hopping pattern. In such systems, each network uses a different sequence of sub-bands to transmit and receive packets, called a “frequency hopping pattern,” to reduce collisions between devices belonging to different networks. A transceiver using this mode of transmission over several frequency bands is called a “frequency hopping” transceiver.
An example of a system implementing frequency hopping is an MB-OFDM UWB system. An MB-OFDM UWB is a wireless communication technology that can be used in many systems including a high data-rate, short-range wireless personal network (WPAN).
The performance of the synchronization has direct implication on the overall system performance as errors introduced by the synchronization, misses in acquisition, estimation errors in timing and carrier frequency offset can degrade the overall system performance significantly.
However, the receiver synchronization circuit has been identified as one of the most power consuming circuits in the baseband section of the radio. This is due to the active duty cycle of the synchronization being generally much higher than other baseband components. Therefore, for applications involving mobile/portable devices, such as applications of MB-OFDM UWB based systems, reduced-power or reduced-complexity solutions for synchronization are needed.